fix(statusbarpart.css): add padding at top of the statusbar

[Grovvik]

Fixes #162995

Description

This PR addresses the visual misalignment of status bar items. Previously, icons and text appeared slightly shifted downwards (by approx 1px) relative to the container's optical center.

Root Cause

The status bar container includes a border-top. While flexbox mathematically centers items within the container (height including border), the visual content area is actually the height minus the border. This caused the items to look "heavy" at the bottom.

Solution

I've adjusted the CSS to compensate for the top border, ensuring items are optically centered within the effective viewing area.

Screenshots

Verification

1. Open VS Code.
2. Zoom in (Ctrl/Cmd + +) to verify the alignment of status bar items (e.g., Git branch, encoding, cursor position).
3. Check in both Light and Dark themes.

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

@bpasero

Matched files:

• src/vs/workbench/browser/parts/statusbar/media/statusbarpart.css

[bpasero]

This does not seem to improve the UX at all on macOS:

[Grovvik]

Thanks! Could you share a before/after comparison on macOS? The misalignment was visible on Windows in browser, but it might be platform-specific. Happy to adjust if needed!

[bpasero]

Here is a before on macOS:

[Grovvik]

Thanks for the screenshots, that really helps!
I'll dive into the CSS to see if I can find a solution that works consistent across all platforms (or target specific platforms if necessary). I will update the PR once I have a better approach.